Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, MN in the Chippewa National Forest. Night electrofishing was conducted in fall 2007 in an attempt to sample young of the year walleye and evaluate natural reproduction. This sampling method has been successfully used in the past on Bowstring and other area lakes to assess relative year class strength. Four standardized stations were sampled for one hour of on-time.\n\nNo young of the year walleye were observed or sampled in this assessment, although several yearling and/or adult walleye were observed on each run. Several thousand shiners and young of the year perch were also observed. This is the fifth time since fall electrofishing sampling began in 1995 that no age-0 walleye were sampled. Catch rates for young of the year walleye have exceeded 20/hour in five of the other assessments. Bowstring Lake has historically shown intermittent years of strong natural reproduction. Environmental conditions may have played a role in the low catch for this assessment. Wind and waves encountered on most stations reduced visibility and made sampling difficult. Low water levels also made it difficult to access and shock the traditional areas of the stations. The low catch rate observed in this assessment may be indicative of a poor year for natural reproduction. Low catches of young-of-the-year walleye were noted on several other large walleye lakes in the area earlier in the year.\n
","surveyDate":"2007-10-03","lengths":{},"surveySubType":"Special Assessment","surveyType":"Targeted Survey"},{"headerInfo":{"wb_type":"Lake","survey_type":"Special Assessment","wb_name":"Bowstring","county":"Itasca","wb_id":"31081300","wb_alt_name":"","survey_id":"4231010938076000","id_date":"2010-09-13"},"narrative":"Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) walleye and suspected yearling walleye. This was the first of two nights of fall electrofishing on Bowstring Lake to compare and evaluate the effectiveness of fall electrofishing for predicting walleye year-class strength. The boat was setup with two spider array droppers, pulsed DC, 4 amps, and 200 volts. The surface water temperature was 62 F and conductivity was 181 omhs. Visibility ranged from poor to moderate depending on the amount of algae. Six of the eight standardized stations were sampled for a total of 91 minutes on-time.
\n
\nThe spring of 2010 was extremely early and drawn out. Natural reproduction and survival of young walleye appeared to be highly variable among area lakes. In the 2010 assessment, 32 YOY walleye were sampled for a catch rate of 21.2/hr on-time. The fish ranged from 4.8 to 7.6 and had a mean length of 6.2 inches. A total of 18 yearlings were sampled for a catch rate of 11.9/hr on-time.
\n
Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) walleye and suspected yearling walleye. This was the second of two nights of fall electrofishing on Bowstring Lake to compare and evaluate the effectiveness of fall electrofishing for predicting walleye year-class strength. The boat was setup with two spider array droppers, pulsed DC, 4 amps, and 200 volts. The surface water temperature was 57 F compared to 62 F on 9/13/2010. Visibility was classified as moderate for all stations. All of the eight standardized stations were sampled for a total of 104 minutes on-time.
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\nThe spring of 2010 was extremely early and drawn out. Natural reproduction and survival of young walleye appeared to be highly variable among area lakes. In the second assessment, 11 YOY walleye were sampled for a catch rate of 6.3/hr on-time compared to 32 YOY (21.2/hr on-time) in the first assessment. The fish ranged from 5.6 to 7.8 and had a mean length of 6.7 inches. In the second assessment, a total of 19 yearlings were sampled for a catch rate of 10.9/hr on-time compared to 11.9/hr on-time in the first assessment.
\n
Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) walleye and suspected yearling walleye. This was the first sample of two samples of fall electrofishing on Bowstring Lake to compare and evaluate the effectiveness of fall electrofishing for predicting walleye year-class strength. The boat was set up with two spider array droppers, pulsed DC, 4 amps, and 200 volts. The surface water temperature was 68 F and conductivity was 183 omhs. Two consecutive nights of electrofishing were completed for the first sample due to the wind picking up the first night. Visibility was poor the first night and poor to moderate the second night depending on the amount of algae. All eight standardized stations were sampled over a two night period for a total of 121 minutes on-time.
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\nNatural reproduction and survival of young walleye appeared to be good among area lakes. In the 2011 assessment, 110 YOY walleye were sampled for a catch rate of 54.6/hr on-time. The fish ranged from 4.4 to 6.6 and had a mean length of 5.4 inches. A total of 3 yearlings were sampled for a catch rate of 1.5/hr on-time.
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Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) walleye. This was the first of two scheduled samples of fall electrofishing on Bowstring Lake to compare and evaluate the effectiveness of fall electrofishing for predicting walleye year-class strength but the second sample was not completed due to poor weather and time. The boat was setup with two spider array droppers, pulsed DC, 4.0 amps, and 200 volts. The surface water temperature was 65 F. Water levels were low and visibility was moderate for all stations.
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\nNatural reproduction and survival of young Walleye appeared to be poor among area lakes. In the 2015 survey, 4 YOY Walleye were sampled for a catch rate of 2.0/hr on-time. The fish ranged from 5.2 to 6.6 inches and had a mean length of 5.9 inches. Numerous (> 100) Walleye less than three years old were observed but not sampled.
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\nAnglers should note that reproduction and recruitment is variable in Walleye populations. Fall electrofishing can be an effective tool to document Walleye reproduction and/or survival to their first fall when conducted as part of a long-term evaluation, but inidividual electrofishing events are often a poor indicator of year-class strength or future angling success.
A targeted survey of the nearshore fish community in Bowstring Lake was conducted by Fisheries Index of Biological Integrity (IBI) Program Staff from 12-15 July 2021. Twenty-four sampling sites were evenly spaced around the lake and each was sampled by backpack electrofishing and seining with a 15-foot or 50-foot seine, where possible. Backpack electrofishing was completed at all 24 sites with one site sampled from the boat. A 50-foot seine was used to sample sixteen sites, a 15-foot seine was used at four sites, and soft sediments with abundant vegetation and deep water prevented the use of seines at four sampling sites. Nearshore sampling captured 21 native species of fish including seven species that are intolerant of disturbance (Banded Killifish, Burbot, Iowa Darter, Longnose Dace, Mimic Shiner, and Rock Bass) and two species (Black Bullhead and Fathead Minnow) that are tolerant of disturbance.
\n
\nA concurrent summer trap net survey was conducted on 12-15 July 2021 by IBI Program Staff. Fourteen trap nets were set along the shoreline that encompassed multiple habitat types. Shorthead Redhorse, Black Crappie, Bowfin, and Bluegill comprised a majority of the trap net catch by number and Bowfin, Shorthead Redhorse, and Silver Redhorse comprised the majority of the catch by biomass. The number of Bluegill sampled per net was below the 25% quartile for similar Lake Class 22 lakes but the average length was 7.3 inches with 63% over 7 inches.
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\nThe nearshore and trap net data were combined with gill net data from an August 2021 survey to describe the fish community and provide a Fish-based IBI (FIBI) score. The FIBI uses fish community data to measure a lake's health, and the types of fish species present can help identify any stressors that may be negatively affecting the lake environment. In Minnesota lakes, certain fish species cannot survive without clean water and a healthy habitat (e.g., Blackchin Shiner, Iowa Darter, and Rock Bass), while other species are tolerant of degraded conditions (e.g., Black Bullhead, Fathead Minnow, and Green Sunfish). The FIBI score, composed of several fish community diversity and composition metrics, indicates the overall health of a lake by comparing it to what is expected for a healthy lake. For additional information on the FIBI, search for \"lake index of biological integrity\" on the mndnr.gov website.
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\nData from this survey indicates Bowstring Lake is in good health as indicated by an FIBI score above the impairment threshold for aquatic life use determined for similar lakes. Data from this survey will contribute biological information about the health of the fish community to the Big Fork River Watershed assessment process in coordination with MN Pollution Control Agency.
Minnesota DNR Fisheries IBI program staff conducted an assessment of lakeshore habitat on Bowstring Lake on May 21st, 2026, following the Score the Shore survey protocols. The assessment consisted of 190 survey sites evenly spaced 400 meters around the lake. Assessments were made in three habitat zones: Shoreline Zone (the shore-water interface to the top of the natural bank), Shoreland Zone (land-ward from shoreline to development structure or 100 feet), and Aquatic Zone (lake-ward 50 feet of shoreline). The average lakewide habitat score was 83.7 (+/- 0.8) out of 100 possible. A score of 83.7 indicates the lakewide shoreline condition is Moderately High (80-84.9). Approximately 15 percent of the sites were developed with a mean score of 64.5 (+/- 2.9) indicating shoreline habitat quality of developed sites is Poor (50-65.9), while undeveloped sites had a mean score of 87.2 (+/- 0.2) with High (85-91.9) habitat quality.
","headerInfo":{"id_date":"2026-05-21","survey_id":"23302628030907001","wb_id":"31081300","wb_name":"Bowstring","county":"Itasca","wb_alt_name":"","survey_type":"Targeted Survey","wb_type":"Lake"},"fishCatchSummaries":[],"surveyID":"23302628030907001","surveyType":"Targeted Survey","surveySubType":"Targeted Survey","lengths":{}},{"lengths":{"WAE":{"fishCount":[[3,1],[10,23],[11,43],[12,17],[13,21],[14,9],[15,6],[16,7],[17,7],[18,6],[19,4],[20,5],[21,3],[22,5],[23,1],[25,1],[6,5],[7,92],[8,12],[9,3]],"maximum_length":25,"minimum_length":3},"BLG":{"minimum_length":7,"maximum_length":9,"fishCount":[[7,4],[8,3],[9,1]]},"PMK":{"maximum_length":8,"fishCount":[[6,1],[7,2],[8,1]],"minimum_length":6},"RKB":{"maximum_length":10,"fishCount":[[10,1],[8,2]],"minimum_length":8},"BRB":{"fishCount":[[10,1],[11,1],[13,2],[14,4]],"maximum_length":14,"minimum_length":10},"BLC":{"minimum_length":4,"maximum_length":11,"fishCount":[[10,34],[11,2],[4,1],[5,44],[6,55],[7,4],[9,16]]},"SLR":{"fishCount":[[21,1],[22,3],[23,3],[24,4]],"maximum_length":24,"minimum_length":21},"TLC":{"minimum_length":7,"fishCount":[[10,1],[15,1],[17,1],[7,1]],"maximum_length":17},"YEP":{"maximum_length":11,"fishCount":[[10,10],[11,1],[4,1],[5,45],[6,43],[7,47],[8,43],[9,24]],"minimum_length":4},"BOF":{"maximum_length":27,"fishCount":[[20,1],[21,2],[22,1],[23,1],[24,2],[25,4],[27,1],[6,1]],"minimum_length":6},"WTS":{"maximum_length":19,"fishCount":[[10,1],[13,2],[14,1],[15,1],[16,9],[17,1],[18,2],[19,2],[8,8]],"minimum_length":8},"SHR":{"minimum_length":12,"fishCount":[[12,1],[13,4],[14,3],[15,1],[16,1],[17,4],[18,6],[19,2]],"maximum_length":19},"NOP":{"fishCount":[[13,1],[14,2],[15,3],[16,13],[17,16],[18,17],[19,25],[20,7],[21,8],[22,2],[23,2],[24,1],[25,1],[26,1]],"maximum_length":26,"minimum_length":13}},"surveySubType":"Population Assessment","surveyType":"Standard Survey","surveyID":"10701413954870000","fishCatchSummaries":[{"totalWeight":5040,"totalCatch":8,"species":"BRB","quartileCount":"0.3-1.7","gearCount":14,"quartileWeight":"0.7-1.1","averageWeight":"1.39","gear":"Standard trap nets","CPUE":"0.57"},{"totalWeight":605,"totalCatch":7,"quartileCount":"0.7-3.7","species":"YEP","gear":"Standard trap nets","averageWeight":"0.19","gearCount":14,"quartileWeight":"0.1-0.2","CPUE":"0.50"},{"averageWeight":"5.51","gear":"Standard trap nets","quartileWeight":"N/A","gearCount":14,"CPUE":"0.79","totalWeight":27485,"totalCatch":11,"quartileCount":"N/A","species":"SLR"},{"quartileCount":"3.0-7.9","species":"NOP","totalCatch":89,"totalWeight":54101,"CPUE":"7.42","gear":"Standard gill nets","averageWeight":"1.34","gearCount":12,"quartileWeight":"1.7-2.8"},{"CPUE":"0.71","gear":"Standard trap nets","averageWeight":"1.28","gearCount":14,"quartileWeight":"N/A","quartileCount":"N/A","species":"NOP","totalCatch":10,"totalWeight":5796},{"CPUE":"0.17","averageWeight":"2.54","gear":"Standard gill nets","quartileWeight":"1.5-2.7","gearCount":12,"quartileCount":"0.1-0.5","species":"SHR","totalWeight":2300,"totalCatch":2},{"species":"RKB","quartileCount":"0.7-3.3","totalWeight":945,"totalCatch":3,"CPUE":"0.21","quartileWeight":"0.2-0.5","gearCount":14,"averageWeight":"0.69","gear":"Standard trap nets"},{"averageWeight":"0.70","gear":"Standard gill nets","quartileWeight":"1.1-1.9","gearCount":12,"CPUE":"22.58","totalCatch":271,"totalWeight":85838,"quartileCount":"4.0-9.6","species":"WAE"},{"species":"BOF","quartileCount":"0.1-0.2","totalCatch":1,"totalWeight":44,"CPUE":"0.08","gearCount":12,"quartileWeight":"3.0-5.2","averageWeight":"0.10","gear":"Standard gill nets"},{"quartileCount":"0.1-0.8","species":"SHR","totalCatch":20,"totalWeight":15494,"CPUE":"1.43","gear":"Standard trap nets","averageWeight":"1.71","quartileWeight":"1.5-4.0","gearCount":14},{"gearCount":12,"quartileWeight":"0.4-1.0","gear":"Standard gill nets","averageWeight":"1.36","CPUE":"0.33","totalWeight":2476,"totalCatch":4,"species":"TLC","quartileCount":"0.5-5.2"},{"averageWeight":"1.31","gear":"Standard gill nets","gearCount":12,"quartileWeight":"1.5-2.3","CPUE":"2.00","totalWeight":14224,"totalCatch":24,"quartileCount":"1.0-3.5","species":"WTS"},{"totalWeight":7020,"totalCatch":102,"quartileCount":"0.2-1.1","species":"BLC","averageWeight":"0.15","gear":"Standard gill nets","quartileWeight":"0.2-0.5","gearCount":12,"CPUE":"8.50"},{"gearCount":12,"quartileWeight":"0.1-0.2","gear":"Standard gill nets","averageWeight":"0.21","CPUE":"17.25","totalWeight":19863,"totalCatch":207,"species":"YEP","quartileCount":"7.1-33.9"},{"totalWeight":782,"totalCatch":4,"quartileCount":"1.6-6.9","species":"PMK","gear":"Standard trap nets","averageWeight":"0.43","quartileWeight":"0.1-0.3","gearCount":14,"CPUE":"0.29"},{"totalCatch":8,"totalWeight":1812,"species":"BLG","quartileCount":"3.7-42.9","gearCount":14,"quartileWeight":"0.1-0.2","gear":"Standard trap nets","averageWeight":"0.50","CPUE":"0.57"},{"CPUE":"0.86","quartileWeight":"3.9-5.1","gearCount":14,"averageWeight":"5.21","gear":"Standard trap nets","species":"BOF","quartileCount":"0.3-1.1","totalWeight":28359,"totalCatch":12},{"totalCatch":3,"totalWeight":3587,"species":"WTS","quartileCount":"0.2-0.8","quartileWeight":"1.4-2.7","gearCount":14,"gear":"Standard trap nets","averageWeight":"2.64","CPUE":"0.21"},{"species":"BLC","quartileCount":"0.3-1.7","totalCatch":54,"totalWeight":14780,"CPUE":"3.86","quartileWeight":"0.3-0.6","gearCount":14,"gear":"Standard trap nets","averageWeight":"0.60"}],"headerInfo":{"wb_alt_name":"","wb_id":"31081300","wb_name":"Bowstring","county":"Itasca","survey_id":"10701413954870000","id_date":"2014-07-28","wb_type":"Lake","survey_type":"Population Assessment"},"narrative":"Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, MN. The lake has four public accesses and moderate shoreline development. The 2009 lake management plan indicates Walleye and Black Crappie as the primary species of management with Northern Pike and Yellow Perch as secondary species. In the spring of 2007 a special Northern Pike regulation was implemented that require all fish from 22 to 36 inches to be released and only one fish over 36 inches could be possessed. The regulation also has an expanded bag limit of nine fish.
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\nBlack Crappie catch rates were above normal for trap nets and gill nets in 2014. Black Crappie were captured at a rate of 3.9/trap net and 8.5/gill net. Gill nets sampled smaller fish than the trap nets. The gill net sample fish ranged from 4.1 to 10.8 inches and averaged 6.2 inches compared to the fish sampled by trap nets that ranged from 5.5 to 11.3 inches and averaged 9.9 inches. Five age classes were identified by scale analysis with fish from 1 to 5 years old represented. Growth was similar to other class 22 lakes. Fish averaged 9.5 inches after four years of growth.
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\nNorthern Pike gill-net catch rates have ranged from 5.7 to 15.8 fish/gill net since 1957. The catches in the last three assessments have been the lowest on record. The catch of 7.4 fish/gill net in 2014 was below the 3rd quartile but did not meet the management goal of 5.0 fish/gill net. The sampled fish ranged from 13.4 to 26.6 inches and averaged 18.9 inches. Eight year-classes were identified from cliethra and scales ranging from 1 to 8 years old. Two and three year old fish represented 24 and 44% of the sample. Northern Pike averaged 20.2 inches after four years of growth which was near the statewide average of 20.5.
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\nWalleye catch rates have fluctuated from 3.5 to 15.0/gill net from 1957 to 2008 and have been near or above the 3rd quartile value of 9.6 since 1988. The record high Walleye catch of 22.6/gill net exceeded the management goal of 7.5 fish/net in 2014. The sampled Walleye ranged from 3.4 to 25.1 inches and averaged 11.3 inches. Thirteen year-classes were identified from scale, opercle, and otolith analysis with fish from 0 to 14 years old. The sample was dominated by small and young fish. Age-1 and age-2 Walleye represented 40 and 29% of the sample. Growth was similar to statewide averages for all ages up to nine years old. Walleye averaged 14.5 inches after four years of growth.
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\nWalleye stocking was discontinued after 1991 because natural reproduction had long been considered an important component of the population. Walleye catches have continued to be excellent since 1991; including the two highest catches on record. Nearly annual fall electrofishing for young-of-the-year Walleye since 1995 has also documented consistent natural reproduction.
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\nYellow Perch gill-net catch rates have fluctuated from a low of 14.4 fish/net in 2008 to a high of 59.0 fish/net in 1980. In 2014, the catch was 17.3 and near the lake class median of 17.1 fish/gill net. The sampled fish ranged from 4.8 to 11.0 inches and averaged 7.5 inches. Age and growth information was not collected in this assessment.
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\nOther species observed during the population assessment included Bluegill, Bowfin, Brown Bullhead, Pumpkinseed Sunfish, Rock Bass, Shorthead Redhorse, Silver Redhorse, Tullibee and White Sucker.
\n
\nIn order to maintain or improve fish and wildlife populations, water quality and habitat must be protected. People often associate water quality problems with large-scale agricultural, forestry, urban development or industrial practices in the watershed. In reality, the impact of land use decisions on one lake lot may be relatively small, yet the cumulative impact of those decisions on many lake lots can result in a significant decline in water quality and habitat. For example, removing shoreline and aquatic vegetation, fertilizing lawns, mowing to the water's edge, installing beach sand blankets, failing septic systems and uncontrolled run-off, all contribute excess nutrients and sediment which degrade water quality and habitat. Understanding these cumulative impacts and taking steps to avoid or minimize them will help to insure our quality fisheries can be enjoyed by future generations.
The numbers of northern pike, perch and bullheads are at quite high levels. Abundance of other fish is within normal limits for this type of lake.
"},{"headerInfo":{"survey_id":"760811539687000","id_date":"2008-09-12","wb_name":"Bowstring","wb_id":"31081300","county":"Itasca","wb_alt_name":"","wb_type":"Lake","survey_type":"Special Assessment"},"surveyDate":"2008-09-12","narrative":"Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, MN in the Chippewa National Forest. Night electrofishing was conducted in fall of 2008 in an attempt to sample age-0 walleye and evaluate natural reproduction. This sampling method has been used annually on Bowstring and other area lakes to assess relative year-class strength. The boat used two spider array anodes and pulsed DC current with an output of 4 amps and 200 volts. The water temperature was 65 degrees and clarity varied from moderate to poor. Windy conditions and an algae bloom limited visibility at some sites. Seven stations were sampled for one hour and forty minutes of on-time.
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\nOnly three young of the year (YOY) walleye were sampled resulting in a catch of 1.8 YOY walleye per hour. Low YOY walleye catches were noted on several similar lakes in 2008, likely a result of the unusually cool, wet spring. As in previous assessments, numerous juvenile and adult walleye were observed on each run, as were several thousand shiners and young of the year perch.
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\nSince annual sampling began in 1995, catches on Bowstring have varied considerably. No YOY walleye were sample in five of 14 assessments while YOY walleye catches exceeded 20/hour in five other assessments. In 2006 and 2007, no YOY walleye were sampled, although low water levels limited sampling to fewer stations and sampling conditions were generally poor. In 2005, YOY walleye were relatively abundant as a catch of 63.7/hr was recorded.
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Bowstring lake is managed primarily for walleye and secondarily for black crappie and northern pike. Walleye were sampled in gill nets at the highest rate on record and at a rate which exceeds the expected range for this type of lake. Most of the fish are smaller, ranging from 6.4 to 22.3 inches in length (mean = 11.0 inches). Aging reveals that most of the walleye were the result of natural reproduction. The apparent high abundance of walleye combined with high numbers of walleye from nonstocked years suggest that natural reproduction is capable of maintaining a strong walleye population. Growth of walleye in Bowstring Lake appears good. Northern pike have historically been very abundant in Bowstring Lake. In this assessment, they were sampled in gill nets at the lowest rate since 1975, yet this rate is still above the expected range. Pike up to 30.9 inches in length were sampled, but they averaged only 19.0 inches in length and 1.5 pounds. Black crappie were sampled in the gill nets at a rate above the expected range. These fish ranged from 4.2 to 12.3 inches in length (mean = 6.8 inches). Crappie were sampled at a rate within their expected range in trap nets. Growth appears to be good. Yellow perch were sampled in the gill nets at the lowest rate on record, but this rate is still within the expected range. They ranged from 4.7 to 11.7 inches in length (mean = 8.9 inches). Only one bluegill was captured in trap nets. This is partly due to low abundance and partly due to the shallow shoalwaters and large bulrush beds which make trap netting difficult. Other species sampled include: white sucker, shorthead redhorse, rock bass, silver redhorse, yellow and brown bullhead, bowfin, burbot and hybrid and pumpkinseed sunfish. Lakeshore residents and users have the ability to insure that Bowstring Lake will continue to produce a quality fishery by practicing wise use of the land and water to preserve water quality and fish habitat. Anglers might also consider practicing catch and release or selective harvest in order to keep the fishery healthy.
","headerInfo":{"wb_type":"Lake","survey_type":"Population Assessment","wb_alt_name":"","wb_name":"Bowstring","county":"Itasca","wb_id":"31081300","survey_id":"106118","id_date":"1996-08-05"}},{"narrative":"Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, MN in the Chippewa National Forest. Night electrofishing was conducted in fall 2009 in an attempt to sample age-0 walleye and evaluate natural reproduction. This was a second round of sampling to evaluate variability in catches from samples obtained on different nights. The boat used two spider-array anodes and pulsed DC current with an output of 5 amps and 250 volts. Conductivity was measured at 193 mmho, surface water temperature was 68.7 F and water clarity was moderate. Weather and temperatures were similar to the previous assessment, but less windy. Eight standardized stations were sampled for 2.0 hours of on-time.
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\nA total of 36 age-0 walleye were sampled in this assessment, for a catch rate of 18.0/hour of on-time. This is a moderate catch rate for Bowstring Lake and similar to the catch rate observed two weeks earlier (23.4/hour). Catch rates have varied from 0 to 63.7/hour in previous years, and have exceeded 20/hour in five of those assessments. Bowstring Lake has historically shown intermittent years of strong natural reproduction. The moderate catch rate observed in this assessment appears to confirm this was a relatively good year for natural reproduction. Low catches of age-0 walleye were recorded in the three previous years (2006 - 2008). Walleye sampled in this assessment ranged from 4.2 to 6.6 inches in length, with a mean length of 5.7 inches. The mean length of walleye was approximately 0.5 inch larger than that of the previous assessment conducted two weeks earlier. Several thousand shiners and young of the year perch were also observed. If multiple nights are sampled in future years, the samples should be spaced over a longer period or conducted under more widely varying conditions.
\n
Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) walleye and suspected yearling walleye. This was the second of two samples of fall electrofishing on Bowstring Lake to compare and evaluate the effectiveness of fall electrofishing for predicting walleye year-class strength. The boat was set up with two spider array droppers, pulsed DC, 4 amps, and 200 volts. The surface water temperature was 61 F compared to 68 F during the earlier sample (9/6/2011). Depending on the station, visibility varied from poor to good due to algae. All of the eight standardized stations were sampled for a total of 119 minutes on-time.
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\nNatural reproduction and survival of young walleye appeared to be good among area lakes. In the second assessment, 140 YOY walleye were sampled for a catch rate of 70.5/hr on-time compared to 110 YOY (54.6/hr on-time) in the first assessment. The fish ranged from 5.0 to 7.1 and had a mean length of 5.8 inches. In the second assessment, one yearling was sampled for a catch rate of 0.5/hr on-time compared to 1.5/hr on-time in the first assessment.
\n
Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) walleye and suspected yearling walleye. This was the first of two scheduled samples of fall electrofishing on Bowstring Lake to compare and evaluate the effectiveness of fall electrofishing for predicting walleye year-class strength but the second sample never occurred due to poor weather and lack of time. The boat was setup with two spider array droppers, pulsed DC, 4 amps, and 200 volts. The surface water temperature was 67 F and conductivity was 183 omhs. Visibility was moderate for all stations. All eight standardized stations were sampled for a total of 125 minutes on-time.
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\nNatural reproduction and survival of young walleye appeared to be variable among area lakes. In the 2012 assessment, 75 YOY walleye were sampled for a catch rate of 35.9/hr on-time. Catch rates have ranged from 0 to 70.5/hr on-time in previous years, and have exceeded 20/hr in seven of those assessments. The fish ranged from 5.2 to 7.7 and had a mean length of 6.4 inches. A total of 19 yearlings were sampled for a catch rate of 9.1/hr on-time. An additional 12 walleye older than age 1 were also sampled.
Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) Walleye and suspected yearling Walleye. This was the first of two scheduled samples of fall electrofishing on Bowstring Lake to compare and evaluate the effectiveness of fall electrofishing for predicting walleye year-class strength but the second sample never occurred due to poor weather and time. The boat was set up with two spider array droppers, pulsed DC, 4.5 amps, and 200 volts. The surface water temperature was 55 F and conductivity was 189 omhs. Water levels were average and visibility was moderate for all stations. We only completed six of the eight standardized stations because the wind was higher than expected. Stations 6 and 9 were excluded and station 10 should not have been conducted because it was too windy.
\n
\nNatural reproduction and survival of young Walleye appeared to be relatively good among area lakes in 2014. We sampled 105 YOY Walleye for a catch rate of 71.2/hr on-time. The fish ranged from 4.1 to 6.4 and had a mean length of 5.4 inches. Despite capturing numerous yearling Walleyes in our August population assessment, we only observed eight in our electrofishing sample. There were not a lot of fish in the shallows where the wind was pounding into the shore.
\n
Walleye are very abundant, evidenced by a gill net CPUE of 12.3. This is higher than the first-third quartile range of 3.7-9.7 for Schupp's lake class #27. The gill net length frequency distibution reveals a wide range of sizes, from 6 to 24 inches, with a large percentage ofthe sample measuring 15 to 19 inches. This is reflected in a moderately high proportional stock density (PSD) value of 59 (n=132). Walleye were sampled in all year classes from 1992 back to 1985, and beyond. 8.9 million walleye fry have been stocked biennially on odd-numbered years. There appears to be good natural reproduction, evidenced by numbered year classes sampled from unstocked years. The 1988 year class is particularly strong, and coincides with an unstocked year. Growth is good. Mean back-calculated length at last annulus formation is age I-5.8\" (n=11), II-9.1\" (n=7), III-11.3\" (n=34), IV-14.3\" (n=40), V-16.1\" (n=20), VI-18.0\" (n=9), and VII-18.2\" (n=4).Northern pike are also very abundant. The gill net CPUE of 12.6 is higher than the lake class #27 first-third quartile range of 3.3-8.4. Northern pike are small. The gill net length frequency distribution signifies a large number of fish between 17 and 19 inches. The gill net PSD is only 13. There are no year class blanks, indicating that natural reproduction is good. The vast stands of wild rice provide excellent spawning habitat for northern pike. Growth is good till age IV, then slows dramatically. Mean back-calculated length at last annulus formation is age I=11.4\" (n=2), II-15.1\" (n=8), III-18.2\" (n=16), IV-20.8\" (n=10), V-20.9\" (n=3), VI-22.1\" (n=3), and age VII-26.3\" (n=2).Black crappie were sampled in average numbers. The gill net catch of 1.2/lift falls within the lake class first-third quartile range of 0.3-1.6. Bowstring Lake has a reputation for producing quality-size crappies. The combined trap net and gill net sample PSD value of 80 reflects this reputation.Important forage species include yellow perch and tullibee. Tullibee abundance is low, the gill net CPUE of 0.3 is below the mid 50% quartile range of 0.8-7.1. Yellow perch were sampled n good numbers. The gill net CPUE of 29.4 falls within the mid 50% quartile range of 8.2-49.3 for lake class #27. Yellow perch attain a size that would be attractive to anglers, 87 out of 135 fish measured in the length frequency distribution are larger than 9\".
","headerInfo":{"survey_id":"106167","id_date":"1992-07-13","wb_alt_name":"","wb_id":"31081300","wb_name":"Bowstring","county":"Itasca","wb_type":"Lake","survey_type":"Population Assessment"}},{"narrative":"Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) Walleye. This was the second of two fall electrofishing surveys in 2017 to compare and evaluate the effectiveness of fall electrofishing for predicting Walleye year-class strength. The boat was setup with two spider array droppers, pulsed DC, 4.0 amps, and 200 volts. The surface water temperature was 57 F. Water levels were very low while visibility was good for all stations.
\n
\nNatural reproduction and survival of young Walleye appeared to be poor among area lakes in 2017. The 5 October 2017 survey sampled 1 YOY Walleye for a catch rate of 0.5/hr on-time. Approximately two weeks earlier on 20 September 2017, 12 YOY Walleye were sampled for a catch rate of 6.2 fish/hr on-time. The results on Bowstring were similar for both samples and appeared to reflect generally poor recruitment for young Walleye.
\n
\nAnglers should note that reproduction and recruitment is variable in Walleye populations. Fall electrofishing can be an effective tool to document Walleye reproduction and/or survival to their first fall when conducted as part of a long-term evaluation, but individual electrofishing events are often a poor indicator of year-class strength or future angling success.
\n
The northern pike, white sucker, black bullhead, black crappie, yellow perch and walleye populations are all above state and local medians but the northern pike and perch populations are not unusually high for this lake. The black bullhead numbers are up from the 1970's but slightly down from the net catches of 1984, while the black crappie population is higher than ever and nice size - the walleye population has steadily increased to its present all time high with a good distribution in size. Other species appear to be in normal numbers for this lake.
","headerInfo":{"survey_id":"105850","id_date":"1988-07-11","wb_name":"Bowstring","wb_id":"31081300","county":"Itasca","wb_alt_name":"","wb_type":"Lake","survey_type":"Population Assessment"}},{"narrative":"Black crappie, northern pike and tullibee populations are at quite high levels. All other fish populations are within normal limits for this type of lake.
","surveyDate":"1975-06-23","headerInfo":{"wb_alt_name":"","wb_name":"Bowstring","county":"Itasca","wb_id":"31081300","survey_id":"106166","id_date":"1975-06-23","wb_type":"Lake","survey_type":"Re-Survey"},"fishCatchSummaries":[{"quartileWeight":"0.4-0.8","gearCount":14,"gear":"Standard trap nets","averageWeight":"0.52","CPUE":"1.57","totalCatch":22,"totalWeight":11.33,"species":"BLB","quartileCount":"0.3-2.1"},{"CPUE":"1.71","quartileWeight":"0.7-1.1","gearCount":14,"averageWeight":"1.38","gear":"Standard trap nets","species":"BRB","quartileCount":"0.3-1.7","totalCatch":24,"totalWeight":33},{"averageWeight":"0.42","gear":"Standard trap nets","gearCount":14,"quartileWeight":"0.1-0.2","CPUE":"5.14","totalCatch":72,"totalWeight":30.28,"quartileCount":"0.7-3.7","species":"YEP"},{"gearCount":9,"quartileWeight":"1.7-2.8","averageWeight":"1.56","gear":"Standard gill nets","CPUE":"8.33","totalCatch":75,"totalWeight":117,"species":"NOP","quartileCount":"3.0-7.9"},{"totalCatch":1,"totalWeight":0.5,"quartileCount":"1.0-6.6","species":"RKB","gear":"Standard gill nets","averageWeight":"0.50","gearCount":9,"quartileWeight":"0.3-0.5","CPUE":"0.11"},{"CPUE":"0.07","gearCount":14,"quartileWeight":"0.7-1.0","averageWeight":"0.30","gear":"Standard trap nets","species":"YEB","quartileCount":"0.9-4.8","totalWeight":0.3,"totalCatch":1},{"quartileCount":"N/A","species":"NOP","totalWeight":17.05,"totalCatch":12,"CPUE":"0.86","averageWeight":"1.42","gear":"Standard trap nets","gearCount":14,"quartileWeight":"N/A"},{"gear":"Standard gill nets","averageWeight":"3.75","gearCount":9,"quartileWeight":"1.5-2.7","CPUE":"0.22","totalCatch":2,"totalWeight":7.5,"quartileCount":"0.1-0.5","species":"SHR"},{"CPUE":"0.11","quartileWeight":"1.0-3.0","gearCount":9,"averageWeight":"2.00","gear":"Standard gill nets","species":"LKW","quartileCount":"0.1-0.9","totalCatch":1,"totalWeight":2},{"totalWeight":2,"totalCatch":5,"quartileCount":"0.7-3.3","species":"RKB","averageWeight":"0.40","gear":"Standard trap nets","gearCount":14,"quartileWeight":"0.2-0.5","CPUE":"0.36"},{"totalWeight":68.55,"totalCatch":54,"quartileCount":"4.0-9.6","species":"WAE","gear":"Standard gill nets","averageWeight":"1.27","quartileWeight":"1.1-1.9","gearCount":9,"CPUE":"6.00"},{"totalWeight":42.5,"totalCatch":12,"species":"SHR","quartileCount":"0.1-0.8","quartileWeight":"1.5-4.0","gearCount":14,"averageWeight":"3.54","gear":"Standard trap nets","CPUE":"0.86"},{"CPUE":"4.78","gear":"Standard gill nets","averageWeight":"0.95","quartileWeight":"0.4-1.0","gearCount":9,"quartileCount":"0.5-5.2","species":"TLC","totalCatch":43,"totalWeight":40.75},{"quartileCount":"1.0-3.5","species":"WTS","totalCatch":22,"totalWeight":41.5,"CPUE":"2.44","averageWeight":"1.89","gear":"Standard gill nets","quartileWeight":"1.5-2.3","gearCount":9},{"quartileCount":"0.2-1.1","species":"BLC","totalWeight":0.5,"totalCatch":3,"CPUE":"0.33","averageWeight":"0.17","gear":"Standard gill nets","gearCount":9,"quartileWeight":"0.2-0.5"},{"totalWeight":89.75,"totalCatch":232,"species":"YEP","quartileCount":"7.1-33.9","gearCount":9,"quartileWeight":"0.1-0.2","gear":"Standard gill nets","averageWeight":"0.39","CPUE":"25.78"},{"averageWeight":"1.35","gear":"Standard trap nets","quartileWeight":"1.0-2.2","gearCount":14,"CPUE":"0.57","totalWeight":10.83,"totalCatch":8,"quartileCount":"0.3-0.9","species":"WAE"},{"CPUE":"0.14","gearCount":14,"quartileWeight":"0.1-0.3","averageWeight":"0.17","gear":"Standard trap nets","species":"PMK","quartileCount":"1.6-6.9","totalWeight":0.35,"totalCatch":2},{"quartileCount":"0.2-0.8","species":"WTS","totalCatch":54,"totalWeight":150.05,"CPUE":"3.86","gear":"Standard trap nets","averageWeight":"2.78","gearCount":14,"quartileWeight":"1.4-2.7"},{"CPUE":"5.57","gearCount":14,"quartileWeight":"0.3-0.6","averageWeight":"0.64","gear":"Standard trap nets","species":"BLC","quartileCount":"0.3-1.7","totalCatch":78,"totalWeight":49.85}],"surveyID":"106166","surveySubType":"Re-Survey","surveyType":"Standard Survey","lengths":{}},{"fishCatchSummaries":[{"totalCatch":27,"totalWeight":4493,"species":"WAE","quartileCount":"N/A","quartileWeight":"N/A","gearCount":1.93194444444444,"gear":"Fall electrofishing","averageWeight":"0.37","CPUE":"13.98"}],"surveyID":"12191712450161007","narrative":"Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) Walleye. This was the first of two fall electrofishing surveys in 2017 to compare and evaluate the effectiveness of fall electrofishing for predicting Walleye year-class strength. The boat was setup with two spider array droppers, pulsed DC, 4.0 amps, and 200 volts. The surface water temperature was 63 to 65 F. Water levels were low while visibility was moderate for all stations. It is unknown how the low water may influence fish location and ultimately our ability to sample them.
\n
\nNatural reproduction and survival of young Walleye appeared to be poor among area lakes in 2017. A total of 12 YOY Walleye were sampled for a catch rate of 6.2 fish/hr on-time. The sampled fish ranged from 5.0 to 6.2 inches and had a mean length of 5.5 inches. An additional 15 Walleye were sampled that ranged from 9.5 to 14.3 inches, likely representing yearlings and two-year-old fish. The initial results on Bowstring appeared to reflect generally poor recruitment for young Walleye.
\n
\nAnglers should note that reproduction and recruitment is variable in Walleye populations. Fall electrofishing can be an effective tool to document Walleye reproduction and/or survival to their first fall when conducted as part of a long-term evaluation, but individual electrofishing events are often a poor indicator of year-class strength or future angling success.
\n
Bowstring Lake is a productive, shallow, 9,220 acre lake located 12 miles northwest of Deer River, MN. The lake has four public accesses and moderate shoreline development. The 2015 lake management plan (LMP) indicates Walleye and Black Crappie as the primary species of management because they are well-suited to the lake and popular with anglers. Northern Pike and Yellow Perch were considered secondary species for management because they also were suited to the lake, though pike size structure is poor and perch size structure is variable. The LMP goals were to maintain a catch of 8.3 Walleye/gill net, reduce the pike catch to 5.0/gill net, and maintain a catch of 3.0 Black Crappie/gill net.
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\nIn the spring of 2007, a special Northern Pike regulation was implemented that required all fish from 22 to 36 inches to be released and only one fish over 36 inches could be possessed. The regulation also had an expanded bag limit of nine fish. In the spring of 2017, the regulation was rescinded and Bowstring moved into the North-central zone regulation for pike (10 fish bag limit, 22 to 26 protected slot with only two over 26 inches).
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\nThe targeted survey in August of 2021 was conducted to assess the fish community, with an emphasis on Northern Pike and Walleye management. The survey was the first since Zebra Mussels were found in Bowstring. A total of 15 gill-nets were set during the survey.
\n
\nBlack Crappie catch rates have been variable since 1957, ranging from 0.3 to 9.2 fish/gill net. The catch of 3.4/net in 2021 was average for the lake and above the LMP goal. The sampled fish ranged from 4.3 to 12.2 inches and averaged 8.1 inches. Six age-classes were identified by scale analysis with fish from age 1 to 7 represented. Growth was comparable to other lakes with similar habitat to Bowstring. Crappie likely provide good fishing when a strong year-class grows to a size angler's desire.
\n
\nBowstring Lake a history of high pike catches with poor size structures. Northern Pike catches have ranged from 5.7 to 15.8 fish/net since 1957. Catches in the prior three surveys were the lowest on record but the catch of 15.6 fish/gill net in 2021 approached the record high. The catch also was nowhere near meeting the management goal of 5.0 fish/gill net. Lower pike populations are desirable because they have better growth, average size, and have less influence on prey within the fish community than high pike populations. The 2021 sampled fish ranged from 14.1 to 32.1 inches and averaged 18.6 inches. Only 9% of the sampled fish were longer than 21 inches. Unfortunately, neither of the regulations since 2007 appear to have made appreciable gains in pike size structure.
\n
\nBowstring Lake has a long history of having a good Walleye fishery maintained by natural reproduction. Walleye catches have ranged from 3.5 to 22.6/net since 1957. The 2021 catch of 10.2 Walleye/net exceeded the management goal of 8.3 fish/net. The sampled fish ranged from 7.7 to 24.0 inches and averaged 14.2 inches. Thirteen age-classes were estimated from bony structures like scales and otoliths (an inner-ear bone) and fish from age 0 to 14 were found. Recruitment appeared good; age-2 fish represented 36% of the sample while another six age-classes represented from 8 to 11% each. Growth was similar to statewide averages for all ages. Walleye averaged 14.6 inches after four years of growth.
\n
\nWalleye stocking was discontinued in 1991 because natural reproduction had long been considered an important component of the population. Five of the six highest Walleye catches have occurred since stocking was discontinued. Frequent fall electrofishing surveys for young-of-the-year Walleye since 1995 has also documented consistent natural reproduction. Continued electrofishing for young Walleye may be an important tool to monitor the population and changing habitat now that Zebra Mussels are established.
\n
\nThe Yellow Perch population in Bowstring Lake has produced a quality fishery at times. Gill-net catches have fluctuated from a low of 7.8 fish/net in 2021 to a high of 59.0 fish/net in 1980. The record low catch in 2021 reflects declining trends observed throughout the state from 1970 to 2013. There is also some evidence the declining trends in gill-net catches is related to perch maturing at earlier ages than before, resulting in smaller size distributions that are less vulnerable to be captured in the gear. The low perch catches also correspond to high Walleye catches and near record high pike catches in Bowstring. High predator numbers may be directly effecting perch catches because of predation (actually fewer perch) or indirectly by the predation creating a response for perch to mature earlier, resulting in slower growth so the smaller perch are less catchable. The 2021 sampled fish ranged from 5.1 to 11.9 inches and averaged 6.9 inches. Additional research should help us better understand these complex ecosystems.
\n
\nOther species observed during the targeted survey included Bluegill, Bowfin, Brown Bullhead, Rock Bass, Shorthead Redhorse, Tullibee and White Sucker.
Bowstring Lake is a 9,220-acre lake in north-central Itasca County within the Bigfork River watershed. Bowstring Lake is approximately 12 miles north of Deer River, MN. The lake has a maximum depth of 32 ft and 4,736 littoral acres. Four public accesses are located around the lake. Bowstring Lake is connected to Sand Lake through a navigable channel. Walleye gill-net catch was 7.5/net, which was within the expected range for similar lakes and similar to the average of 8.2/net in past assessments. The abundance in this assessment declined from recent assessments when the gill-net catch was 15.0 and 12.3/net in 1996 and 1992, respectively. Size structure was good with several fish between 16 and 19 inches, however few fish greater than 20 inches. Growth was similar to the statewide average for fish ages one to eight and slower than the statewide average for fish ages 9 and 10. Bowstring Lake has excellent natural reproduction, and has not been stocked with walleye fry since 1991. Although the gill-net catch declined in this assessment, fluctuations are expected in natural walleye populations. Walleye fry stocking from 1970 to 1991 did not increase walleye abundance compared to surveys sustained by natural reproduction. Forty percent of the fish sampled in this assessment were from the 2001-year class and fall electrofishing conducted in 2002 sampled a record high 74 young-of-the-year/hour. Both surveys indicate two strong year classes, which should increase the population in the near future.Northern pike gill-net catch was 5.7/net, which was within the expected range for similar lakes. Abundance in 2002 was lower than past assessments, which has varied from 8.3 to 15.8/gill net and averaged 11.9/gill net. This is the first assessment that northern pike abundance has been within the expected range. Size structure was poor with few fish greater than 20 inches. Size structure has historically been poor, because high northern pike abundance often results in slow growth. A lower abundance northern pike population is favorable, because it can result in better growth and improved size structure.Black crappie gill-net catch was 8.2/net, which was much higher than the expected range. Abundance in past assessments has varied from 0.3 to 9.2/gill net. Size structure was moderate with a good year class of fish between eight and nine inches. Growth was slower than the statewide average for ages one and two and similar to the statewide average for ages three through six. Yellow perch gill-net catch was 18.5/net, which was within the expected range for similar lakes. Abundance in past assessments varied from 15.7 to 59.0/gill net. Size structure was moderate with a few fish greater than nine inches. Other fish sampled include bluegill, bowfin, pumpkinseed sunfish, rock bass, shorthead redhorse, silver redhorse, white sucker, and yellow bullhead.
","headerInfo":{"wb_alt_name":"","wb_id":"31081300","wb_name":"Bowstring","county":"Itasca","id_date":"2002-08-05","survey_id":"106812","survey_type":"Population Assessment","wb_type":"Lake"},"surveySubType":"Population Assessment","surveyType":"Standard Survey","lengths":{"PMK":{"minimum_length":3,"maximum_length":7,"fishCount":[[3,1],[5,1],[6,1],[7,6]]},"RKB":{"maximum_length":10,"fishCount":[[10,2],[5,1]],"minimum_length":5},"BRB":{"maximum_length":13,"fishCount":[[10,10],[11,109],[12,70],[13,7]],"minimum_length":10},"SLR":{"fishCount":[[19,1],[21,3],[22,9],[23,12],[24,4]],"maximum_length":24,"minimum_length":19},"BOF":{"maximum_length":27,"fishCount":[[19,1],[20,4],[21,3],[24,3],[25,1],[26,2],[27,1]],"minimum_length":19},"NOP":{"maximum_length":31,"fishCount":[[10,1],[12,2],[13,3],[14,1],[15,1],[16,8],[17,14],[18,21],[19,19],[20,16],[21,7],[22,2],[23,1],[26,1],[31,1]],"minimum_length":10},"BLB":{"fishCount":[[10,6],[14,1],[9,3]],"maximum_length":14,"minimum_length":9},"WAE":{"fishCount":[[12,2],[13,2],[14,8],[15,8],[16,13],[17,12],[18,8],[19,11],[20,4],[21,3],[22,1],[23,2],[24,1],[6,1],[7,2],[8,25],[9,16]],"maximum_length":24,"minimum_length":6},"TPM":{"maximum_length":3,"fishCount":[[3,1]],"minimum_length":3},"BLG":{"fishCount":[[4,2],[5,2],[8,1]],"maximum_length":8,"minimum_length":4},"YEB":{"maximum_length":9,"fishCount":[[9,1]],"minimum_length":9},"BLC":{"maximum_length":12,"fishCount":[[1,1],[10,7],[11,2],[12,1],[5,4],[6,22],[7,28],[8,80],[9,8]],"minimum_length":1},"TLC":{"minimum_length":12,"maximum_length":16,"fishCount":[[12,1],[16,1]]},"YEP":{"minimum_length":1,"maximum_length":11,"fishCount":[[1,1],[10,24],[11,3],[4,5],[5,101],[6,52],[7,24],[8,31],[9,44]]},"SHR":{"maximum_length":24,"fishCount":[[14,3],[15,11],[16,14],[17,12],[18,4],[19,5],[23,1],[24,1]],"minimum_length":14},"WTS":{"minimum_length":5,"fishCount":[[10,1],[11,5],[12,6],[13,3],[14,1],[15,8],[16,20],[17,18],[18,18],[19,4],[21,1],[5,2],[6,9],[9,1]],"maximum_length":21}}},{"surveySubType":"Special Assessment","surveyType":"Targeted Survey","lengths":{},"fishCatchSummaries":[],"surveyID":"760629937448000","surveyDate":"2006-10-09","narrative":"Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, MN in the Chippewa National Forest. Night electrofishing was conducted in fall 2006 in an attempt to sample young of the year walleye and evaluate natural reproduction. This sampling method has been successfully used in the past on Bowstring and other area lakes to assess relative year class strength. Four standardized stations were sampled for one hour of on-time.
\n
\nNo young of the year walleye were observed or sampled in this assessment, although several yearling and/or adult walleye were observed on each run. Several thousand shiners and young of the year perch were also observed. This is the fourth time since fall electrofishing sampling began in 1995 that no age-0 walleye were sampled. Catch rates for young of the year walleye have exceeded 20/hour in five of the other assessments. Bowstring Lake has historically shown intermittent years of strong natural reproduction. Environmental conditions likely played a role in the low catch for this assessment. Sampling occurred following the passage of a major cold front, and water temperatures were substantially lower than preferred for this type of sampling. Low water levels also made it difficult to access and shock the traditional stations. For these reasons, it is believed the low catch rate may not be truly indicative of a poor year for natural reproduction. Moderate to good catches were noted on several other large walleye lakes in the area earlier in the year.
\n
Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing (with SR-16S) was conducted to sample young-of-the-year (YOY) walleye and suspected yearling walleye. This was the first of two scheduled samples of fall electrofishing on Bowstring Lake to compare and evaluate the effectiveness of fall electrofishing for predicting walleye year-class strength but the second sample never occurred due to poor weather and time. The boat was setup with two spider array droppers, pulsed DC, 4 amps, and 200 volts. The surface water temperature was 63 F and conductivity was 188 mhos. Water levels were low and visibility was moderate for all stations. All eight standardized stations were sampled for a total of 120 minutes on-time.
\n
\nNatural reproduction and survival of young walleye appeared to be variable among area lakes. In the 2013 assessment, 16 YOY walleye were sampled for a catch rate of 8.0/hr on-time. The fish ranged from 5.6 to 7.5 and had a mean length of 6.7 inches. A number of 2+ walleye were observed throughout the night but the few potential yearlings were not measured.
Bowstring Lake is moderately large, shallow hardwater lake well suited for sustained production of walleyes and northern pike. Substantial populations of these species are now present in the lake. However, the age-composition of walleyes in the test net catches indicated a relatively poor hatch of this species in 1953 and 1951. These weak year-classes presumably furnished the bulk of the anglers' catch during 1955 through 1957, and their low abundance undoubtedly was a substantial contributing factor to the reported slump in walleye fishing. A relatively strong 1954 year-class of walleyes should enter the anglers' catch in 1958 and improve fishing success.Yellow perch are not unusually abundant for lakes of this type. Population densities for the other species considered are normal for lakes of this type with the exception of the substantial crappie population. Although crappies are numerous at present, reproductive success for this species is apparently sporadic, and considerable fluctuation in fishing success should be expected.Growth rates are normal for all species except for northern pike which are slower growing then usual for lakes of this type. This comparatively slow growth is probalby related to the high population density of northern pike in this lake, and resultant competition for food and space.
","surveyDate":"1957-06-19","surveyID":"106165","fishCatchSummaries":[{"quartileWeight":"0.4-1.0","gearCount":11,"gear":"Standard gill nets","averageWeight":"0.11","CPUE":"0.27","totalCatch":3,"totalWeight":0.33,"species":"TLC","quartileCount":"0.5-5.2"},{"gear":"Standard gill nets","averageWeight":"0.33","gearCount":11,"quartileWeight":"0.7-1.2","CPUE":"0.09","totalWeight":0.33,"totalCatch":1,"quartileCount":"0.3-1.6","species":"BRB"},{"gear":"Standard gill nets","averageWeight":"1.40","quartileWeight":"1.7-2.8","gearCount":11,"CPUE":"11.45","totalWeight":176.4,"totalCatch":126,"quartileCount":"3.0-7.9","species":"NOP"},{"gearCount":11,"quartileWeight":"0.2-0.5","averageWeight":"0.14","gear":"Standard gill nets","CPUE":"1.55","totalWeight":2.4,"totalCatch":17,"species":"BLC","quartileCount":"0.2-1.1"},{"totalWeight":39.2,"totalCatch":22,"quartileCount":"1.0-3.5","species":"WTS","averageWeight":"1.78","gear":"Standard gill nets","gearCount":11,"quartileWeight":"1.5-2.3","CPUE":"2.00"},{"quartileWeight":"0.1-0.2","gearCount":12,"gear":"Standard trap nets","averageWeight":"0.17","CPUE":"2.33","totalWeight":4.8,"totalCatch":28,"species":"YEP","quartileCount":"0.7-3.7"},{"totalCatch":2,"totalWeight":0.8,"species":"RKB","quartileCount":"0.7-3.3","gearCount":12,"quartileWeight":"0.2-0.5","gear":"Standard trap nets","averageWeight":"0.40","CPUE":"0.17"},{"totalCatch":45,"totalWeight":43.6,"species":"WAE","quartileCount":"4.0-9.6","quartileWeight":"1.1-1.9","gearCount":11,"averageWeight":"0.97","gear":"Standard gill nets","CPUE":"4.09"},{"totalWeight":5.2,"totalCatch":10,"species":"BRB","quartileCount":"0.3-1.7","quartileWeight":"0.7-1.1","gearCount":12,"averageWeight":"0.52","gear":"Standard trap nets","CPUE":"0.83"},{"CPUE":"0.50","gear":"Standard trap nets","averageWeight":"1.18","quartileWeight":"N/A","gearCount":12,"quartileCount":"N/A","species":"NOP","totalWeight":7.1,"totalCatch":6},{"species":"BLC","quartileCount":"0.3-1.7","totalWeight":4.6,"totalCatch":7,"CPUE":"0.58","quartileWeight":"0.3-0.6","gearCount":12,"gear":"Standard trap nets","averageWeight":"0.66"},{"gearCount":11,"quartileWeight":"1.5-2.7","gear":"Standard gill nets","averageWeight":"2.24","CPUE":"0.91","totalWeight":22.4,"totalCatch":10,"species":"SHR","quartileCount":"0.1-0.5"},{"quartileCount":"0.2-0.8","species":"WTS","totalCatch":2,"totalWeight":4.6,"CPUE":"0.17","averageWeight":"2.30","gear":"Standard trap nets","gearCount":12,"quartileWeight":"1.4-2.7"},{"CPUE":"0.09","gearCount":11,"quartileWeight":"N/A","gear":"Standard gill nets","averageWeight":"0.00","species":"CSH","quartileCount":"N/A","totalWeight":0,"totalCatch":1},{"totalWeight":0.6,"totalCatch":2,"species":"WAE","quartileCount":"0.3-0.9","gearCount":12,"quartileWeight":"1.0-2.2","averageWeight":"0.30","gear":"Standard trap nets","CPUE":"0.17"},{"quartileCount":"0.1-0.8","species":"SHR","totalWeight":59.6,"totalCatch":26,"CPUE":"2.17","averageWeight":"2.29","gear":"Standard trap nets","gearCount":12,"quartileWeight":"1.5-4.0"},{"quartileCount":"7.1-33.9","species":"YEP","totalWeight":121.8,"totalCatch":444,"CPUE":"40.36","averageWeight":"0.27","gear":"Standard gill nets","quartileWeight":"0.1-0.2","gearCount":11}]},{"lengths":{"WAE":{"minimum_length":4,"maximum_length":5,"fishCount":[[4,8],[5,35]]}},"surveyType":"Targeted Survey","surveySubType":"Special Assessment","surveyID":"4230913338702004","fishCatchSummaries":[{"CPUE":"23.38","gear":"Fall electrofishing","averageWeight":"0.00","gearCount":1.83916666666667,"quartileWeight":"N/A","quartileCount":"N/A","species":"WAE","totalWeight":0,"totalCatch":43}],"headerInfo":{"survey_id":"4230913338702004","id_date":"2009-09-09","wb_name":"Bowstring","wb_id":"31081300","county":"Itasca","wb_alt_name":"","wb_type":"Lake","survey_type":"Special Assessment"},"narrative":"Bowstring Lake is a class 22 lake located 12 miles northwest of Deer River, MN in the Chippewa National Forest. Night electrofishing was conducted in fall 2009 in an attempt to sample age-0 walleye and evaluate natural reproduction. This sampling method has been successfully used in the past on Bowstring and other area lakes to assess relative year class strength. The boat used two spider-array anodes and pulsed DC current with an output of 5 amps and 200 volts. Water clarity was moderate to poor. Windy conditions made sampling difficult at some stations. Eight standardized stations were sampled for approximately 1 hour and 50 minutes of on-time.
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\nA total of 43 age-0 walleye were sampled in this assessment, for a catch rate of 23.4/hour of on-time. This is a moderately high catch rate for Bowstring Lake. Catch rates have varied from 0 to 63.7/hour in previous surveys, and have exceeded 20/hour in five of those assessments. Bowstring Lake has historically shown intermittent years of strong natural reproduction. The moderate catch rate observed in this assessment may be indicative of a relatively good year for natural reproduction. Low catches of age-0 walleye were recorded in the three previous years (2006 - 2008). Walleye sampled in this assessment ranged from 4.4 to 5.9 inches in length, with a mean length of 5.2 inches. Several thousand shiners and young of the year perch were also observed.
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The purpose of this targeted survey was to collect information on the health of the Walleye population. The age and length at which female Walleye become mature and the biomass of adult female Walleye (pounds/acre) were the specific indicators that were investigated. The results indicate the Walleye population should continue to do well with the current management practices despite there being evidence of fairly high angling mortality.
","surveyDate":"2015-09-22","lengths":{"WAE":{"fishCount":[[10,7],[11,42],[12,31],[13,17],[14,15],[15,4],[16,3],[17,5],[18,4],[19,6],[20,4],[22,3],[23,2],[24,2],[27,1],[7,10],[8,14],[9,8]],"maximum_length":27,"minimum_length":7},"LMB":{"minimum_length":5,"maximum_length":5,"fishCount":[[5,5]]},"RKB":{"maximum_length":10,"fishCount":[[10,1]],"minimum_length":10},"TLC":{"fishCount":[[12,2],[13,2],[14,1],[17,3],[18,1],[7,1],[8,17],[9,8]],"maximum_length":18,"minimum_length":7},"YEP":{"minimum_length":5,"maximum_length":11,"fishCount":[[10,6],[11,2],[5,7],[6,31],[7,29],[8,12],[9,18]]},"BLC":{"minimum_length":4,"maximum_length":11,"fishCount":[[10,4],[11,6],[4,51],[5,5],[7,5],[8,32],[9,24]]},"NOP":{"minimum_length":13,"fishCount":[[13,1],[15,1],[16,2],[17,5],[18,12],[19,19],[20,16],[21,14],[22,7],[23,4],[24,2],[25,1],[27,1]],"maximum_length":27},"WTS":{"minimum_length":6,"fishCount":[[10,2],[11,1],[13,1],[14,2],[15,2],[16,3],[17,1],[18,6],[19,2],[6,9],[7,3],[8,8],[9,4]],"maximum_length":19}},"surveyType":"Targeted Survey","surveySubType":"Targeted Survey"},{"surveyDate":"2008-08-04","narrative":"Bowstring Lake is a class 22 lake that outlets through Inger, MN. The lake has four public accesses, several resorts, and moderate shoreline development. The 2003 lake management plan indicates black crappie and walleye as the primary species of management with northern pike and yellow perch as secondary species.
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\nThe walleye gill-net catch rate (10.1 fish/net) exceeded the management goal of 8.1 fish/net. Previous assessment catch rates have ranged from 3.5 to 15.0 since 1957. The sampled fish ranged from 9.3 to 25.6 inches and had a mean length of 13.9 inches. Eight year classes were identified from scale and bony structure analysis with fish from two to nine years old. The 2005 and 2006 year classes represented 44 and 30% of the sample. Walleye were last stocked in Bowstring Lake in 1991, therefore, natural reproduction was responsible for all the walleye sampled in 2008. Growth was similar to statewide averages for all ages. Walleye averaged 15.4 inches after four years of growth.
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\nThe black crappie trap-net catch (0.7 fish/net) and gill-net catch (0.9 fish/net) were at or above their respective lake class medians. The fish from both gears ranged from 3.5 to 12.6 inches. Two size groups were obvious from the length frequency histogram; fish from 3.5 to 5.0 inches and fish from 10.5 to 12.5 inches. Although five year classes from age 1 to age 8 were documented, age-1 fish represented 83% of the sample. Growth was generally above statewide averages for all ages but still within 15% of the mean.
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\nThe northern pike gill-net catch was 5.8 fish/net. The 2008 catch was similar to the 2002 catch of 5.7 fish/net and near the lake class median of 5.0 fish/net. The last two assessments had the lowest catch rates on record and were distinctly lower than all other assessments dating back to 1957 (range was 8.3 to 15.8 fish/net). Spring water levels due to the snow melt can affect the success of northern pike reproduction. Lower northern pike catches may partially be explained by the generally mild winters the area experienced for approximately 10 years prior to 2007. In 2008, the sampled fish ranged from 12.9 to 32.2 inches and had a mean length of 20.1 inches. Eight year classes were identified from cliethra and scales ranging from age 1 to age 8. Three and four year old fish were the most common. Northern pike averaged 20.4 inches by age 4 which was near the statewide average of 20.5.
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\nYellow perch gill-net catch rates have fluctuated from a low of 14.4 fish/net in 2008 to a high of 59.0 fish/net in 1980. Although the 2008 catch was lower, it was still near the lake class median of 17.1 fish/net. The sampled fish ranged from 5.2 to 11.7 inches and had a mean length of 7.4 inches. The yellow perch population may not attract a lot of attention by anglers due to the lack of larger fish but it still provides an important function in the fish community as prey. Age and growth information was not collected in this assessment.
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\nTullibee are a species that can be difficult to sample but are also important to fish communities as a prey source. The gill-net catch rate was 0.6 fish/net in this assessment which is just above the 1st quartile for this lake class. Tullibee catch rates have been as low as 0.1 fish/net and as high as 4.8 fish/net with no apparent trend in abundance. The fish ranged from 8.2 to 17.1 inches and had a mean length of 12.8 inches.
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\nOther species observed during the population assessment included bowfin, black bullhead, brown bullhead, largemouth bass, pumpkinseed sunfish, shorthead redhorse, silver redhorse, white sucker, and yellow bullhead.
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\nIn order to maintain or improve fish and wildlife populations, water quality and habitat must be protected. People often associate water quality problems with large-scale agricultural, forestry, urban development or industrial practices in the watershed. In reality, the impact of land use decisions on one lake lot may be relatively small, yet, the cumulative impact of those decisions on many lake lots can result in a significant decline in water quality and habitat. For example, removing shoreline and aquatic vegetation, fertilizing lawns, mowing to the edge of the water, installing beach sand blankets, failing septic systems and uncontrolled run-off, all contribute excess nutrients and sediment which degrade water quality and habitat. Understanding these cumulative impacts and taking steps to avoid or minimize them will help to insure our quality fisheries can be enjoyed by future generations.
Northern pike population is at a high level. This can be attributed to abundant spawning area. The walleye population is down slightly because of two weak year classes. The perch population is high and more than adequate to support the predator population.
","surveyDate":"1980-07-07","headerInfo":{"id_date":"1980-07-07","survey_id":"105569","wb_alt_name":"","wb_name":"Bowstring","county":"Itasca","wb_id":"31081300","survey_type":"Population Assessment","wb_type":"Lake"},"surveyType":"Standard Survey","surveySubType":"Population Assessment","lengths":{}},{"surveyID":"21682525937763000","fishCatchSummaries":[],"headerInfo":{"survey_id":"21682525937763000","id_date":"2025-09-16","wb_name":"Bowstring","wb_id":"31081300","county":"Itasca","wb_alt_name":"","wb_type":"Lake","survey_type":"Targeted Survey"},"narrative":"Bowstring Lake is located 12 miles northwest of Deer River, Minnesota. Fall, night electrofishing was conducted to sample young-of-the-year (YOY) Walleye. The survey was the first since adult zebra mussels were found in 2020. The surface water temperatures and weather were good for sampling young Walleye.
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\nWater levels were very low and visibility was clear for all stations. The sampling stations that were previously considered very good were now full of vegetation following the introduction of zebra mussels, especially water celery. Lakes with relatively low to no vegetation in the electrofishing stations have consistently been better for sampling YOY Walleye. If these conditions remain, sampling young Walleye will likely become more challenging in the future.
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\nAnglers should note that reproduction and recruitment is variable in Walleye populations. Fall electrofishing can be an effective tool to document Walleye reproduction and/or survival to their first fall when conducted as part of a long-term evaluation, but individual electrofishing events are often a poor indicator of year-class strength or future angling success.
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\nNatural reproduction and survival of young Walleye appeared to be poor among area lakes in 2025. The seven stations were sampled for more than 1 hour and 35 minutes and no YOY Walleye were observed. Ten adult Walleye were observed and they appeared in good condition. Substantially more Largemouth Bass and panfish were noted. Some stations had abundant shiners and YOY Yellow Perch, though only one adult perch was observed. A few YOY Burbot, modest numbers of Brown and Yellow Bullhead, and small, skinny Northern Pike were also observed.